#11 - added syntactic sugar for associations

lib/factory_girl/factory.rb

@@ -123,6 +123,35 @@ class Factory
     add_attribute(name, *args, &block)
   end
 
+  # Adds an attribute that builds an association. The associated instance will
+  # be built using the same build strategy as the parent instance.
+  #
+  # Example:
+  #   Factory.define :user do |f|
+  #     f.name 'Joey'
+  #   end
+  #
+  #   Factory.define :post do |f|
+  #     f.association :author, :factory => :user
+  #   end
+  #
+  # Arguments:
+  #   name: (Symbol)
+  #     The name of this attribute.
+  #   options: (Hash)
+  #     factory: (Symbol)
+  #       The name of the factory to use when building the associated instance.
+  #       If no name is given, the name of the attribute is assumed to be the
+  #       name of the factory. For example, a "user" association will by
+  #       default use the "user" factory.
+  def association (name, options = {})
+    name    = name.to_sym
+    options = options.symbolize_keys
+    association_factory = options[:factory] || name
+
+    add_attribute(name) {|a| a.association(association_factory) }
+  end
+
   def attributes_for (attrs = {}) #:nodoc:
     build_attributes_hash(attrs, :attributes_for)
   end

test/factory_test.rb

@@ -168,6 +168,46 @@ class FactoryTest < Test::Unit::TestCase
 
     end
 
+    context "when adding an association without a factory name" do
+
+      setup do
+        @factory = Factory.new(:post)
+        @name    = :user
+        @factory.association(@name)
+        Post.any_instance.stubs(:user=)
+      end
+
+      should "add an attribute with the name of the association" do
+        assert @factory.attributes_for.key?(@name)
+      end
+
+      should "create a block that builds the association" do
+        Factory.expects(:build).with(@name, {})
+        @factory.build
+      end
+
+    end
+
+    context "when adding an association with a factory name" do
+
+      setup do
+        @factory      = Factory.new(:post)
+        @name         = :author
+        @factory_name = :user
+        @factory.association(@name, :factory => @factory_name)
+      end
+
+      should "add an attribute with the name of the association" do
+        assert @factory.attributes_for.key?(@name)
+      end
+
+      should "create a block that builds the association" do
+        Factory.expects(:build).with(@factory_name, {})
+        @factory.build
+      end
+
+    end
+
     should "add an attribute using the method name when passed an undefined method" do
       @attr  = :first_name
       @value = 'Sugar'

test/integration_test.rb

@@ -12,7 +12,7 @@ class IntegrationTest < Test::Unit::TestCase
 
     Factory.define 'post' do |f|
       f.name   'Test Post'
-      f.author {|a| a.association(:user) }
+      f.association :author, :factory => :user
     end
 
     Factory.define :admin, :class => User do |f|